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United States Patent | 5,189,446 |
Barnes ,   et al. | February 23, 1993 |
A cylindrical plasma reaction chamber is equipped with a pair of axially separated solenoid coils and a multipole magnet structure extending between the coil pair. An axially-directed magnetic field and a transverse cusp field are respectively provided by the coils and the magnet. A working gas is contained within the chamber and is excited by applied microwave energy. The strengths of the two magnetic fields and the microwave frequency value are selected to produce a substantially closed electron cyclotron resonance (ECR) zone of proper size. This ECR zone is located axially between the solenoid fields. Baffling is used to separate the closed plasma ECR zone from the workpiece region of the chamber. A semiconductor wafer is positioned within the workpiece region to intercept most plasma particles which follow the axially directed magnetic lines passing through the ECR zone. Few of the particles from the closed ECR zone travel to destinations other than the wafer.
Inventors: | Barnes; Michael S. (Mahopac, NY); Forster; John C. (Poughkeepsie, NY); Keller; John H. (Poughkeepsie, NY) |
Assignee: | International Business Machines Corporation (Armonk, NY) |
Appl. No.: | 702654 |
Filed: | May 17, 1991 |
Current U.S. Class: | 315/111.41; 313/231.31; 315/111.21 |
Intern'l Class: | H05H 001/18 |
Field of Search: | 315/111.21,111.41,111.71,111.81 313/231.31 |
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Paper, "Si Etching with Low Ion Energy in Low Pressure ECR Plasma Generated by Longitudinal and Multipole Magnetic Fields", by H. Shindo et al., Proceedings of Symposium on Dry Process, Oct. 30-31, 1989, Tokyo, pp. 21-26. Book, "Introduction to Plasma Physics", by Francis F. Chen, Plenum Press, 1974, pp. 299-300. "Cold and Low Energy Ion Etching with ECR Plasma Using a Hybrid Magnetic Field", by N. Fujiwara et al., Proceedings of Symposium on Dry Process, pp. 15-17, Oct. 30-31, 1989, Tokyo. "Cold and Low-Energy Ion Etching (COLLIE)", by N. Fujiwara et al., Japanese Journal Applied Physics, vol. 28, 1989, pp. 2147-2150. |